Person:
Muñoz Martín, Alfonso

First Name

Alfonso

Last Name

Muñoz Martín

URI

https://hdl.handle.net/20.500.14352/75220

Affiliation

Universidad Complutense de Madrid

Faculty / Institute

Ciencias Geológicas

Department

Geodinámica, Estratigrafía y Paleontología

Area

Geodinámica Interna

Identifiers

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Now showing 1 - 10 of 23

Aplicación del método de resistividades con SEV para la caracterización hidrogeológica de la cuenca de Dajla (Argelia)
(Geogaceta, 2010) Torres López, Sara; Muñoz Martín, Alfonso; Jiménez Díaz, Alberto; Ahmed, Baba; De lorenzo, Javier; García López, Cristina; Olaiz Campos, Antonio José
The aim of this study is the hydrogeological exploration and characterization using Geophisical surveying in the vicinity of Dakhla Basin (Algeria). To that end, it has been used the method of resistivities through Vertical Electric Sounding (VES) on a campaign carried out in April 2009. The work included 19 VES, which have been calibrated with existing wells and with field geological observations. The results have allowed the characterization of Tertiary deposits as well as Ordovician sandstones. With these data, it has been possible to identify the position and thickness of a shallow salty aquifer, and the roof of a deep freshwater aquifer developed on the Ordovician sandstones. The integration of the geometry of the aquifers with the resistivity values obtained in the Ordovician sandstones has allowed the location of a favorable area for the situation of a new well.
Análisis de la geometría en profundidad de fracturas conductoras en zonas de baja permeabilidad mediante tomografía eléctrica (El Berrocal, Sistema Central Español)
(Geogaceta, 2007) Muñoz Martín, Alfonso; Olaiz Campos, Antonio José; Vicente Muñoz, Gerardo de; Antón López, Loreto; Elorza, Francisco José; Vicente, Raquel de
The groundwater flow in zones of low permeability, as granites, is mainly associated with zones of fracture. For this reason the characterization of the fractures is fundamental, both in surface as in depth, and must integrate geological information (geological mapping, structural analysis), geophysics (mainly electrical and electromagnetic methods) and geochemistry (radon and others gases) with hydrogeology. In this work we analyze the geophysical response of a strike-slip fault zone by means of three 2D resistivity models. The objective is to investigate the presence of several conductive zones and their geometry in depth. The obtained results allow to control the geometry in depth of the fractures, the gaps between the different mapped traces along the fault zone as well as the thickness of landfill. All this information will be useful for the hidromechanical simulation of the massif, and to check the geometry and gas permeability calculated from emanometry.
Inversion of moment tensor focal mechanisms for active stresses around the Microcontinent Iberia: Tectonic implications
(Tectonics, 2008) Vicente Muñoz, Gerardo de; Cloetingh, Sierd; Muñoz Martín, Alfonso; Olaiz Campos, Antonio José; Stich, Daniel; Vegas, Ramón; Galindo-Zaldívar, Jesus; Fernández Lozano, Javier
The Iberian microcontinent and its connected oceanic crust are affected by deformations related to the Eurasian-African plate boundary. Active stress inversions from populations of moment tensor focal mechanisms have been performed around and inside the Iberian peninsula, using a total of 213 moment tensor estimates. Main results are: 1) The tensorial solutions show better consistency and lower misfits compared to those obtained previously from first P arrival focal mechanisms. 2) Along the Eurasia- Africa western boundary, the type of active stresses progressively changes easternwards from triaxial extension to uniaxial compression along the Terceira Ridge, the Gloria Fault zone and the Gulf of Cadiz. 3) In the Betics-Alboran-Rif zone, uniaxial extension predominates with Shmax N155ºE trending. 4) In N Algeria, uniaxial compression reappears. 5) The Iberian foreland is currently under strike-slip to uniaxial extension tensorial conditions.
Longest and still longer: The Messejana-Plasencia dyke and its links with later Alpine deformation belt in Iberia
(Tectonophysics, 2021) De Vicente Muñoz, Gerardo; Olaiz Campos, Antonio José; Muñoz Martín, Alfonso; Cunha, Pedro P.
The Messejana-Plasencia dyke (End-Triassic), NE-SW oriented, is the longest simple structure in Iberia (~500 km) and constitutes a first-order rheological discontinuity that crosses the entire crust. During the Alpine deformation, this discontinuity nucleated the Messejana-Plasencia left-lateral strike-slip fault and its related strike-slip deformation belt, consisting of a series of wide coalescent stepovers and small basins developed on the footwalls. Both structures can be followed from offshore of SW mainland Portugal to the central sector of the Spanish-Portuguese Central System. Using tectonic, geophysical, magnetic, and gravimetric analyses, our study demonstrated that it extends NE more than ~100 km below the continental sediments of the Duero Cenozoic Basin, until the Iberian Chain. We used a tectonostratigraphic analysis to determine the age of the wrench fault movement and that of the Spanish-Portuguese thrusts. In this range, the largest displacement during the Cenozoic occurred in the southern thrust of the Spanish sector of the Central System over the Madrid Cenozoic Basin, and NE-SW trending. This thrust displaces the Moho more than 10 km and probably joins the Messejana-lasencia strike-slip fault at depth. The deduced age movement for both is Oligocene-Lower-Middle Miocene, related to the intraplate stresses transmitted from the Pyrenean orogen towards its foreland. A strain partitioning process was then deduced for the simultaneous movement of both main Alpine faults in Central Iberia.
El cabalgamiento cenozoico de Boinás (Cordillera Cantábrica, España)
(Geogaceta, 2007) Vicente Muñoz, Gerardo de; González Nistal, S.; Muñoz Martín, Alfonso; Vegas, Ramón; Olaiz Campos, Antonio José; Fernández Lozano, Javier; Vicente, Raquel de
The opencast gold mine of Boinás, has allowed to outcrops the contact between the variscan basement and the Cenozoic sediments. It is observable that the contact is a post - Lower Oligocene thrust, with a N40ºE trend. From a macrostructural point of view, Boinás thrust spreads along more than 10 km with a constant orientation, a vertical gap that reaches 400 m, and a NW vergence. Northwestwards another Alpine thrust develops (Tineo, A l o n s o y Pulgar , 2004) with a parallel orientation an opposite vergence. Between both thrusts a tectonic pop-down appears (Narcea Pop-down). The dynamic analysis shows that this structure was activated by a paleostress tensor with an horizontal s1 trending N139ºE, with a stress regime close to uniaxial compression (R=0.06). This stress allows the geometrical interchanges between s2 and s3. The outcrop also allows to observe a secondary population of normal faults, that fits to an extensional stress tensor (R=0.01) with s3 trending N146ºE, that is coaxial with the main compressive stress tensor. We interpret both fault populations as generated by the tectonic thrust emplacement.
Mapa de esfuerzos de Europa a partir de Mecanismos focales calculados desde el Tensor de Momento Sísmico
(Geogaceta, 2006) Olaiz Campos, Antonio José; Vicente Muñoz, Gerardo de; Muñoz Martín, Alfonso; Vegas, Ramón
This work shows a new stress map for Europe obtained from the inversion of earthquakes focal mechanisms calculated with the centroid tensor method (Dzieownski et al., 1982). An amount of 1608 focal mechanisms have been selected with several quality criteria from different catalogues (CMT Harvard, ETH, Med-Net, I.G.N. and I.A.G.) from 1973 to present-day. Values for the maximum horizontal stress and the shape factor of the ellipsoid (horizontal/vertical stress) have been calculated following the Reches (1983) and De Vicente (1988) slip model. The local results have been interpolated to a 1ºx1º regular grid in which the relation between tectonic horizontal stress and vertical load has been taken into account. The final map shows a good correlation with the primary tectonic forces generated in the plate boundaries and the local perturbations related with main crustal heterogeneities as suggested by Gölke and Coblentz (1996).
El terremoto de Haití
(Enseñanza de las ciencias de la tierra, 2011) Granja Bruña, José Luis; Carbó Gorosabel, Andrés; Hernáiz-Huerta, Pedro Pablo; Llanes Estrada, Pilar; Muñoz Martín, Alfonso; Olaiz Campos, Antonio José
Análisis de la estructura alpina de la corteza del centro de la Península Ibérica: Una sección Magneto-Telúrica a través del Sistema Central (Sierra de Gredos)
(Geotemas, 2012) Pous, Jaume; Muñoz Martín, Alfonso; Olaiz Campos, Antonio José; Seillé, H.; De Vicente Muñoz, Gerardo
We present a magnetotelluric profile across the Duero basin, the Central System and the Madrid basin, acquired in the framework of the TOPO-IBERIA project. The MT profile consists of 24 magnetotelluric sites over a 200 km, NS oriented profile. Five components were measured with periods ranging from 0.001 s to 500s. The dimensional analysis reveals a dominant E-W direction and 2D joint inversion of apparent resistivity, phases and tipper was carried out. The inverse resistivity model obtained has been compared with other geological and geophysical data, and it shows a resistive and homogeneous crust that extends towards the Duero basin. The main conductive anomalies are elongated and inclined bodies that are related with the main big–scale Alpine thrusts. Other superficial conductive bodies are related with the tertiary sedimentary basins. [RESUMEN]Este trabajo muestra un nuevo perfil magnetotelúrico (MT) a través del la cuenca del Duero, el Sistema central y la Cuenca de Madrid, adquirido dentro del proyecto TopoIberia. El Perfil MT consiste en 24 sondeos a lo largo de 200 km con una orientación NS. En cada sondeo se han medido cinco componentes con periodos de 0.001 a 500 s. El análisis dimensional revela una dirección dominante E-O y se ha realizado una inversión conjunta en 2D de las resistividades aparentes, fases y tipper. El modelo de resistividades obtenido ha sido comparado con otros datos geológicos y geofísicos, y muestra una estructura cortical homogénea y resistiva que se prolonga hacia la cuenca del Duero. En esta corteza aparecen cuerpos conductores inclinados y alargados en profundidad asociados a grandes cabalgamientos alpinos. Otros cuerpos conductores superficiales están claramente relacionados con las cuencas sedimentarias terciarias
El cabalgamiento de Valdesotos: consecuencias de la acomodación del acortamiento cenozoico en el zócalo del Sistema Central
(Geotemas, 2004) Olaiz Campos, Antonio José; Vicente Muñoz, Gerardo de; Vegas, Ramón; González Casado, José Manuel; Muñoz Martín, Alfonso; Álvarez, J.
We describe and study structural evidences concerning to Alpine tectonics at NE sector o f the Spanish Central System (SCS). In Valdesotos area, the Hercynian basement is uplifted over Mesozoic sediments, throughout a main SW verging thrust. Fault population analysis and geological mapping has been used to look at the relation between structures in the basement and in the cover. As a consequence of accommodation of strains in the basement, kink folds are developed, such as secondary thrust and folds in the tegument. All these meso- and macrostructures seem to answer to a shortening in agreement with the Cenozoic deformation.
Aplicación del método electromagnético de inducción ligera para el análisis de la permeabilidad en medios fracturados (granito de “El Berrocal”, Sistema Central Español)
(Geogaceta, 2009) Vicente, Raquel de; Muñoz Martín, Alfonso; Olaiz Campos, Antonio José; Antón López, Loreto; Vicente Muñoz, Gerardo de
Fracture characterization in granites has been an important subject of study during these last years, by means of geological-structural cartography, hydrogeology and geochemical analysis. All these works have been carried out to investigate the hydromechanics and permeability in low-permeability rocks. In this study we apply a surface geophysical method in order to characterize the permeability of the fault zones affecting “El Berrocal” granite (Central System, Spain). The low-induction electromagnetic method (EM) gives us the apparent resistivity values of the rocks at a maximum depth, allowing us to differentiate between soil / altered rock from fresh granites. As the apparent resistivity depends on the granite alteration and/or the water content, this parameter allows to estimate the relative permeability of different fracture zones. The obtained results show that the high-permeability fractures are those that are larger ones which were active during Alpine deformation (Eocene-present).